MRI vs CT – the differences
MRI or CT scan? – one of the most frequently asked questions by patients. Both scans provide 3D images of the body, but they work in different ways. I will explain when a doctor chooses an MRI, when a CT scan, and why newer does not always mean better.
In this article
How MRI and CT work – the fundamental difference
A CT scan uses X-rays. Great for bones and air (lungs). An MRI uses a strong magnetic field and radio waves. Great for soft tissues. No radiation in an MRI = safe for repeated use.
When to choose MRI, when to choose CT
MRI is better for: the brain, spinal cord, joints, muscles, disc herniation, pelvis, prostate, breasts. CT is better for: fractures, acute haemorrhagic stroke, lungs, embolism, acute conditions in A&E.
Duration and cost
CT: 1–5 minutes, privately PLN 250–600. MRI: 20–45 minutes, privately PLN 400–1,500. The National Health Fund (NFZ) reimburses both, but waiting times are long. APERTA: MRI appointments within 24–48 hours.
Radiation and safety
Single CT scan = dose of 2–10 mSv (annual background dose 2–3 mSv). Repeated CT scans accumulate the dose. Critical in children. MRI: no radiation, can be repeated. Main risks of MRI: metallic foreign bodies, certain pacemakers.
When to use both methods
Often complementary. Brain tumour – MRI + CT for calcifications. Head injury – CT in A&E (haemorrhage), MRI follow-up. Polytrauma – whole-body CT in A&E, MRI selectively.
Frequently asked questions
I am allergic to CT contrast – can I have MR contrast?
Yes, gadolinium (MRI) is chemically different from iodinated contrast (CT).
I have a pacemaker – can I have an MRI?
Most new pacemakers are MRI-compatible.
Is MRI more accurate than CT?
Not always. CT is better for bones. MRI is better for soft tissues.
I have claustrophobia – will a CT scan be easier?
Yes, a CT scan takes 1–5 minutes. But the APERTA open MRI eliminates claustrophobia.
Is CT radiation dangerous?
A single CT scan – very low risk. Multiple scans in young people = a real risk.
This content is for information purposes only and does not replace a medical consultation.
